Firearm



April 18, 1967 w. A. CENTER FIHEABM 2 Sheets-Sheet l Filed Deo. 2, 196'4April 18, 1967 w. A. CENTER 3,314,183

FIREARM Filed Dec. z, 1964 2 sneetssheet z mwN @Y 7V7'r'e2a A. C'eFrZ 27M 1.77%,

7 W9 A WJNN .fl./ m N/ 7 y 4N ww w @www QN N+ United States Patent O3,314,183 FIREARM Warren A. Center, Westminster, Mass., assignor toHarrington & Richardson, Inc., Worcester, Mass., a corporation ofMassachusetts Filed Dec. 2, 1964, Ser. No. 415,307 3 Claims. (Cl. 42-69)This invention relates principally to semi-automatic firearms of thetype including a combined gas-operated and blow-back action whereinthere is provided gas-operated piston means for unlocking the bolt andinitiating the rearward travel thereof after the cartridge is fired,whereupon the blow-back continues the action to move the bolt to itsrearwardmost position for ejecting the spent cartridge case andincluding means for returning the bolt once more to locked breech-closedposition with a new cartridge in place, ready for the next shot. Thefiring mechanism may include a disconnector for repositioning a part ofthe sear operating mechanism to allow the sear and trigger to be movedto cocked condition.

Objects of the invention include the provision of a firearm as abovedescribed in which the gas-operated portion of the mechanism deviatesfrom the White principle by having the force of the gas directed to theforward portion of the piston, causing the same to be retracted to aventing location and to impress its force upon the forward end of anaction bar which is connected to the bolt for unlocking it, to the endthat the gas-operated portion of the device is made simpler and lessexpensive as well as more positive in its action; and the provision of agasoperated devi-ce of the class described including very simple andeffective means for interdicting the action of the gas piston, so thatthe firearm becomes a manually operated device for single shots,throwing grenades, etc.

A still further object of the invention resides in the provision of anew and improved firing mechanism for firearms including aspring-pressed pivoted hammer and a new and improved sear, this searhaving a pivoting action about an axis which is closer to the hammeraxis than is the interconnection between the Sear nose and the hammer,whereby pressure of the hammer on the sear is in a direction topositively prevent accidental tiring by the sear nose slipping off thehammer, and as a matter of fact the greater the pressure in thisdirection, the greater is the force by which the sear is maintained inposition.

A further object of the invention resides in a new and improved safetydevice which acts directly on the trigger and has a portion in thetrigger guard by which it is easily moved to inactive condition of thesafety, but at the same time the safety can be moved back to safetycondition upon a pull in a rearward direction, i.e., in the samedirection as the trigger pull, the safety being very closely associatedtherewith for quick andeasy operation thereof.

A still further object of the invention resides in the provision of anew and improved receiver plug including means so that the same isalways located in exactly the same position regardless of how often itmay be removed and reapplied to the receiver.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which:

FIG. 1 is a View of the firearm in elevation with the fore end removed;

FIG. 2 is an enlarged view with parts removed and in section showing theaction as it appears in cocked condition ready to fire;

FIG. 3 is a longitudinal sectional view showing the gas operatingmechanism; Y

FIG. 4 is a section on line 4 4 of FIG. 3;

ice

FIG. 5 is a section on line 5 5 of FIG. 2 through the breech plug;

FIG. 6 is a bottom plan view of the rear end of the bolt;

FIG. 7 is a top plan view of the rear end of the action box, and

FIG. 8 is a sectional view showing a modified bolt.

In illustrating the invention it must be understood that any kind ofstock can be utilized and therefore the stock has not been shown butonly the parts of the firearm which are pertinent to the invention. Inthis case there is a barrel 10 to which the receiver 12 is attached byany desired or convenient means. At the under side of the barreladjacent the muzzle there is a vent 14 through which the explosion gasesproceed to enter the gas cylinder which is indicated at 16. This gascylinder is secured to the `barrel by any desired means such as beingwelded thereto or the like. In the gas cylinder there is a piston 18which has a head portion 20 containing a chamber receiving the expandinggas. This chamber leads to a smaller chamber 22 and the action is thatthe gas entering the larger chamber first is in effect slowed to reducethe otherwise sharp flow of the piston 18 in its rearward motioncontacting the forward end 24 of the action bar 26. This causes theaction bar to be retracted smoothly against the action of the action barspring 28. The action bar spring returns the action bar piston and boltto breech-closed position of the firearm as will be described more fullyhereinafter.

There is a gas plug generally indicated at 30 which can be turned by itshead or by a screwdriver or the like and this plug is threaded into theforward end portion of the gas cylinder as at 32.` It is generallycylindrical and hollow in form and is provided with a radial vent 34which is normally aligned with vent 14 so that the gas enters the gasplug and impinges upon the head of the cylinder as described. Howevermerely by lturning the gas plug a slight amount the vent 14 will be cutoff and when this vent is cut off the automatic action of the firearm iscompletely inhibited.

The bolt of the firearm is indicated at 36 and when it is in forwardbreech closed condition with the firearm ready to fire, it is locked inthis position with the rear portion thereof in a tapered recess 38 inthe receiver 12. When the action bar moves rearwardly, the bolt iscammed down by reason of the cams 35 on the engaging cams 37 in thebolt, and this causes the bolt to be pushed out of recess 38 and back,see the dotted lines, FIG. 2. The action bar thus unlocks the bolt fromthe notch 38 and moves it rearwardly, for the ejection of the spent caseand the admission of a fresh cartridge into the receiver. The blow-backaction aids this motion to some degree. The magazine and appurtenantparts are not shown herein as they form no part of the presentinvention.

When the action bar spring returns the action bar, the latter moves thebolt forwardly, and another action bar cam at 39 acts on cam surface 41on the bolt to raise the rear end of the bolt into locked breech closedcondition. The top of the cam 41 at 42 holds the bolt until the actionbar once more retracts.

The `firing mechanism is shown in FIG. 2. This firing mechanism islocated in general in a housing 50 mounted by any kind of bolts withrespect to the receiver, one of these bolts being located at 52.Pivotally mounted at 54 is a disconnector bar or lever 56 which has aforward end portion or nose at 58 in the path of the action bar, see forinstance 60, which depresses the disconnector at i-ts right-hand endportion at 58. Thus as the action bar retracts, it raises the other endat 59 for a purpose to be described, and releases it only at the extremeend of the forward travel of the action bar.

The hammer is indicated in general at 62. It has a hammer nose 464 andis pivoted at 66 in the housing 50. A spring 68 urges the hammer up tofiring position. The sear is shown at 70. It has a sear nose '72 and ispivoted at 74. There is also a sear spring 716 tending to turn the searin a counterclockwise direction. The hammer in the area near its nosehas a cam surface 78 cooperating with a similar cam surface 80 on thesear nose, and it will be seen that the hammer 62 is caused to move in aclockwise or refractive direction under intiuence of the bolt, and whenthis happens the cam surfaces 78 and 80 engage causing the sear to moveslightly in a clockwise direction against the action of the sear spring76, so that the nose 64 snaps under the sear nose at 72 and the hammeris thereby held in the position of FIG. 2, ready to be released by thesear to fire the next shot.

There is a trigger indicated at 82 mounted on a trigger pin 84 andhaving a spring at 86 for maintaining it in its forward position in thetrigger guard 88. The spring tends to maintain the trigger in thisposition and returns it to this position after the trigger has beenpressed to release the sear. The trigger has an abutment at the lowerend thereof as at 90 and there is a rectilinearly actuated safety device92 which can be moved to safety position by pressing with the finger atthe forward portion thereof and retracting the safety to the rear. Asshown in dotted lines at 94, there is an abutment on the safety toengage the trigger abutment 90 and the trigger is positively heldagainst firing thereby. It is only necessary to push forwardly with theforetinger in the trigger guard in order to release the safety.

At the end of the sear 70 opposite the sear nose, there is a shoulder 98which is engaged by an inclined shoulder 100 on a sear latch or releasemember .102. The sear latch is pivoted at 104 and it holds the searagainst the action of the sear spring, but is capable of moving in acountercloekwise direction under iniiuence of the trigger so that theinclined shoulder at 100 depresses the sear and causes it to moveslightly in a clockwise direction, in turn causing the sear nose to slipoff the hammer nose and allow the hammer 62 to move in itsanti-clockwise direction under iniiuence of its spring 68 to strike thefiring pin in the bolt. The sear latch 2 is retracted about its pin 104against the action of its spring 106 by means of the disconnector end 59which is in the form of a cam, engaging a iixed pin 107 on the latch.Thus the latch is completely free of the sear at all times except whenthe action bar is fully forward and the bolt thus locked. Hence the guncannot be red unless the bolt is locked in Ithe breech. Also, thetrigger upon being pressed, prevents the sear from re-engaging thehammer unless released. Hence, no premature firing is possible.

The new and improved breech-plug comprises a generally cylindricallymember 108 which can be c-ut off at 110 to make the same conform to thegeneral shape desired, and this member is pinned at 112 to a plug 114screw-threaded into the breech end of the receiver as at 116. The breechplug member 108 abuts the receiver on a flat annular area 118, and pin112 lies in an annular groove in the member y108.

It is recognized that breech plugs have to be turned up very tightly andwhen they are removed and replaced they are apt to vary in iinalposition, but in the present case the member 108 abuts right up againstthe fiat at 118 at the rear end of the receiver, and then the screw 108merely holds the same in position.

The sear spring impinges upon the top surface of the safety 92 and has acap thereon which is indicated at 120. This cap fits into either one oftwo depressions at 122 and thus the sear spring tends to hold the safetyin whichever position it is placed under manual pressure. The safety canalso have a stop pin located in a groove as is shown at 124 to preventover-riding.

Now referring lto FIG. 8, a modification in the bolt is here shown. Thereceiver is indicated by the reference numeral 126 and it is undercut orlnotched at 128 to receive an upstanding projection on the top of thebolt at 130, in which case the bolt is tilted and locked in breechclosedposition. The interengagement between the bolt and the action bar is thesame as before, but in this case the top surface of the bolt which isindicated at 132 is chamfered or rounded ofi? along a taper indicated at134. As shown in dotted lines in IFIG. 8, the bolt moves back and forthbut when the action bar brings it so that the projection at is in linewith the notch 128, the cams mentioned above, as at 39 and 41, ensurethat the bolt shall be moved up at its rear end into breech-closed andlocked position, and in this case of course the rear end of the bolt istilted upwardly from the bottom surface of the receiver.

The advantage of this construction is that it is easier to chamfer offthe top of the bolt than it is to form the taper for recess 38 in thereceiver which is shown in FIG. 2, and thus this results in a saving inthe manufacture of the firearm. Insofar as the cams on the bolt areconcerned, the numerals are applied to FIG. 8 the same as they are toFIG. 2, and it is believed that this will result in clarity ofillustration.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:

`1. A firing mechanism for a firearm including a barrel, a receiverthereon, a reciprocable bolt therein, an action bar for moving said boltrearwardly to open the breech, a hammer, a hammer pin upon which saidhammer is pivoted, a sear, a sear pin for the sear, said sear and hammerhaving interengaging means whereby the sear normally holds the hammer inretracted position thereof ready for tiring, a spring for said hammer tomove it to firing position, and means to move said sear to hammerreleasing position to allow said hammer spring to spring the hammer intofiring condition, the distance between the sear pin and the hammer pinbeing shorter than the distance between the sear-hammer interengagingmeans and the hammer pin, whereby pressure of said hammer upon the searunder influence of said spring causes locking pressure on said searrather than tending to move the sear to hammer releasing position, and aspring for the sear normally tending to urge the sear towardshammerengaging position and into the path of the hammer as it moves tococked position, the hammer and sear having cooperating cam surfaces toallow the hammer to pass the sear so that the interengaging means canoperate.

2. A firing mechanism for a firearm including a barrel, a receiverthereon, a reciprocable bolt therein, a hammer, a hammer pin upon whichsaid hammer is pivoted, a sear, a sear pin for the sear, a spring forthe sear urging the sear toward hammer engaging position in the path ofthe hammer, said sear and hammer having interengaging means whereby thesear normally holds the hammer in retracted position thereof ready forfiring, and mating cam means to allow the hammer to pass the searsutiiciently to cause interengagement of said means, a spring for saidhammer to move it to firing position, and means to move said sear tohammer releasing position against the action of the sear spring to allowsaid hammer spring to move the hammer into tiring condition, the searpin on which the sear pivots being in a position relative to thelocation of the interengaging means such that pressure of said hammerunder influence of said hammer spring enhances locking pressure on saidsear and prevents accidental discharge of the firearm.

3. A breech plug construction for the receiver of a firearm having astock, the receiver having an opening at the rear thereof, in which saidopening is defined and surrounded by a iiat face generally annular area,said breech plug construction including a generally cylindrical eX-posed member having a substantially fiat annular forward face adapted tobe placed in contact with the fiat face at the opening, and a threadedbreech plug threaded into the receiver in the area of the fiat faces,said breech plug having a head contacting, holding and clamping saidmember with its fiat face in flat clamped condition with respect to the'at face at the opening of the receiver, said exposed member also havinga stock contacting face generally at right angles to the annular forwardat face, and a stock engaging pin protruding from said stock contactingface.

References Cited by the Examiner UNITED STATES PATENTS Herren 42-70Horan 89-184 Reising 42-16 Klocker 42--17 Harvey 89-193 Simpson 89-193Campbell 42-69 Janson et a1. 4217 Hailston et al. 89-193 Lochhead 89-193

1. A FIRING MECHANISM FOR A FIREARM INCLUDING A BARREL, A RECEIVER THEREON, A RECIPROCABLE BOLT THEREIN, AN ACTION BAR FOR MOVING SAID BOLT REARWARDLY TO OPEN THE BREECH, A HAMMER, A HAMMER PIN UPON WHICH SAID HAMMER IS PIVOTED, A SEAR, A SEAR PIN FOR THE SEAR, SAID SEAR AND HAMMER HAVING INTERENGAGING MEANS WHEREBY THE SEAR NORMALLY HOLDS THE HAMMER IN RETRACTED POSITION THEREOF READY FOR FIRING, A SPRING FOR SAID HAMMER TO MOVE IT TO FIRING POSITION, AND MEANS TO MOVE SAID SEAR TO HAMMER RELEASING POSITION TO ALLOW SAID HAMMER SPRING TO SPRING THE HAMMER INTO FIRING CONDITION, THE DISTANCE BETWEEN THE SEAR PIN AND THE HAMMER PIN BEING SHORTER THAN THE DISTANCE BETWEEN THE SEAR-HAMMER INTERENGAGING MEANS AND THE HAMMER PIN, WHEREBY PRESSURE OF SAID HAMMER UPON THE SEAR UNDER INFLUENCE OF SAID SPRING CAUSES LOCKING PRESSURE ON SAID SEAR RATHER THAN TENDING TO MOVE THE SEAR TO HAMMER RELEASING POSITION, AND A SPRING FOR THE SEAR NORMALLY TENDING TO URGE THE SEAR TOWARDS HAMMERENGAGING POSITION AND INTO THE PATH OF THE HAMMER AS IT MOVES TO COCKED POSITION, THE HAMMER AND SEAR HAVING COOPERATING CAM SURFACES TO ALLOW THE HAMMER TO PASS THE SEAR SO THAT THE INTERENGAGING MEANS CAN OPERATE. 